Selector switch for telecommunication systems



July 1, 1947. I F. VAN LAETHEM 2,423,

' V SELECTOR SWITCH FOR TELEQpMMUNICATiQN SYSTEMS I Filed Feb. 12, 1945 2 Sheets-Sheet 1 ATTORNEY Patented July I 194 SELECTOR SWITCH FOR TELECGMliIUNI- CATION SYSTEMS Frans Van Laethem, Antwerp, Belgium, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application February 12, 1943, Serial No. 475,686 In the Netherlands September 12, 19M

Claims.

This invention relates to shafts with grooves, which are angularly spaced at different axial positions and to means such as molds of making such shafts.

One example of an embodiment of the invention is the formation of a molded shaft having at least one spiral groove, such as a molded worm shaft.

Such worm shafts are used in automatic telephony and may be applied in selectors such as is disclosed in British Patent No. 522,198.

Shafts are known, which are provided with projections thereon, such as spiral ribs and means are known for making such shafts of molded material, by using a plurality of unitary molded sections.

However, such constructions, provided with projection or ribs, have various disadvantages. In the cases of endless spirals or worms, special precautions have to be taken at thecrossing points of the spiral in order to' prevent the guided member leaving its correct path. It may further be desirable to strengthen the construction by giving the spiral rib heavier dimensions. In such a case, however, the interrupted length at the crossing points of the spiral becomes too large.

These disadvantages can be avoided by using shafts, made according to this invention, using grooves. At the crossing points of the spiral, the isolated guide projections, required in the case of shafts with spiral ribs to prevent the guided member leaving its correct path, can be omitted. The interruptions at the crossing points are also much shorter, securing a better guidance for the sliding member. Furthermore, it can be seen that grooved spirals are of much stronger construction than spiral ribs.

One feature of the invention is that the shaft comprises a plurality of unitary molded sections, which are assembled and positively held from rotation relative to each other, and are provided with grooves, which are at different cross-sections of each section angularly spaced relative to one another. Each section may comprise at least one-half of the pitch of a spiral, if the grooves are spirally arranged on the shaft.

The sections comprise intermediate sections, which all have the same form, and end sections of another form. Together these sections may in one embodiment provide a right and left handed endless spiral groove around the shaft. These sections have further a special form in this respect, that the divisional lines between the separate sections are along a line of the side wall of the grooves. The molds required for making the sections, comprise two members, the parting lines of which follow, therefore, the line of the side wall of the grooves. In this way the molding problem becomes extremely simple.

One embodiment of the invention will be described by means of the drawing, showing a shaft with endless grooves by means of which an axially movable member can be given reciprocatory movement by continuous rotation of the shaft in one direction. Also further molding means are shown in the drawing for making such shafts.

Fig. 1 shows a plan view of the worm shaft with a central steel shaft;

Fig. 2 shows an elevation view of the shaft, but without the central part;

Fig. 3 shows an end view of the shaft of Fig. 2;

Fig. 4 shows the plan view of an end section;

Fig. 5 shows a side view of an end section;

Fig. 6 shows a plan view of a penultimate section;

Fig. '7 shows a side view of a penultimate section;

Fig. 8 shows a plan view of an intermediate section;

Fig. 9 shows a side view of an intermediate section;

Fig. 10 shows an end View of an intermediate section;

Fig. 11 shows, in section, the mold for forming a section according to Figs. 8, 9 and 10;

Figs. 12 and 13 show the upper part of the mold for forming a section of the worm shaft, as shown in Fig. 6;

Figs. 14 and 15 show the lower part of the mold, in which a section of the worm shaft, as shown in Figs. 6 and 7, is formed, while Figs. 16, 17 and 18 show the respective upper parts of the mold, which is used for making a section of the form shown in Figs. 4 and 5.

If it is required to mold a shaft in phenol condensation products or other suitable synthetic molding products, the shaft is divided into sections each incorporating one-half of the pitch of the grooved spiral l in Fig. 1. All intermediate sections 1 are then identical in form and are molded in the same mold. The end sections 8, however, are different, because the spiral groove is continuous at the extremities of the shaft. Special mold members are, therefore, provided for the end sections which can be placed in the same mold. The method of mounting the section to form a complete shaft is shown in Figs. 1 and 2. The left-hand shaft section 8 abuts against a collar 6 which springs into a groove of the spindle 3. The sections may be held together by the pressure of the spring 4, which spring is provided between the right-hand extreme end and a collar 5, fixed in the same way as collar 6.

The application of the invention is, of course,

not limited to the illustrated method ofmounting which is basedon the principle of; holding the shaft assembled by spring pressure. Any suitable other method may therefore also be applied, for.

instance, the hollow sections may be threaded on a spindle and be held in place bynutsyscrewedy on the spindle. Another construction may be that the hollow shaft sections are-formed with-cooper-- I ating ribs and slots to preventyrelativeyrotatiorrand are positioned between hollow :endmembersy:

which fit the end of a wire spoke, riveted, for... instance, at one end and provided'm ith thread i and nut at the other end, securing together in this way the assembly.

To prevent in the embodiment, as shown, the Shaft s c i .f -r ativeati nandocu eper-fect lining upqof" thesersections they may be 5 provided in their.hollow -interior portion with a rib 2 which cooperates with a longitudinal groove 1 in the spindle 3.

The mold (Figall-lcomprises-a main part-9,

the closur pieces .lflyand l I-; will which the up er and'the lower mold members: l2 and-J 3 are fixed asalsopart M, in which the core-Idis-mounted The, guide pins, l6 and 51; assurethat-iall. these mold part s be .kept -in- .-their;exact. correcttrnutual 1:vositi( ns .-v The dowel pins .IB and. l9:'=serve for.-

fixingthe upper and lower mold members in their respective closing portionsjll and I I The 1 upper mold member I 2 is provided with a tapered chanel 20 for theinjectionpfathe molding compound. -Fonmolding.endasections fii gs=.'v 6 and 7) the lower mold member l3=of Fig.-; 11=is replaced by the lowenmcldmember as shownin;Fig.;l4 and 15... Formoldingthe extreme end-sections (Figs.

4 and 5) the upper mold member 12 of Fig. '7 is.

replaced by the upper. member. shown ,in- Figs.: .16

and 17 and the lower mold member [2 by ;the

lowermoldmember shown in. Fig. 18;

A similar mold may, of course, be provided -fop grooves which are at different cross-sections of each section angularly spaced relative to oneanother,.wherebythegrooves of each section cooperate with the grooves of an adjacent section ,so; :as'- to give" substantially the effect of a continuously grooved, shaft.

2. ;Shaftfiaccording'to claim 1, in which the grooves'are'arranged so as together to form a spiral: extending the length of the shaft.

3. Shaft according to claim 1, in which each section includes at least one-half of; the pitchyof a grooved-spiral.

4. Shaft. according to -claim. 1,;in .whichwthe grooves in the intermediate sections-form two;

spirals; one right-hand and one left-hand while the .grooves in the end sections extend -so as.-to connectsaidltwo spirals,.whereby an; endless-spiralis formed, so that continuous rotation of theshaft will.afford-reciprocating motion of a memberriding .in said spirals.

5. Shaft according to "0131111191, in which themeans :for holding together the sections include spring means for exerting .-aXial l pressure.- upon said. sections.

FRANS VAN LAETHEM:

REFERENCES CITED.

The following references :aret-of: recordin the".

file. .of this patent:

UNITED STATES PATENTS.

Numberz Name Date 1,354t,"734.-:- Furguson Oct-5.1119205 1398,335 Von Hamba'ch June17,'1924:c 1,9 l3;440.:' Friele H.June 13,:1933 

